In general, a window installed in the building can provide various functions, such as ventilating polluted indoor air, looking outside as well as having natural lighting within the building.
Such a window includes a window frame which is provided in the building, and a window door of sliding or hinged type which is provided with the window frame. In casing of conventional windows with the above-mentioned construction, ventilation is enabled by opening a window in such a manner that outdoor air is inhaled directly into the building for ventilating indoor air.
Ventilation using such conventional windows has an advantage that indoor air can be ventilated within a short period of time through opening windows; however, it has a problem in that outdoor noise travels into the building.
Also, there is a problem that indoor air may be polluted by an intake of outdoor smoke, smog, yellow dust, pollen, etc. when a window is opened for ventilation.
Furthermore, while ventilating by opening windows in the winter season, there is a problem that room temperature decreases rapidly by an intake of cold outdoor air into the building, thereby consuming additional energy for operating heating system additionally to increase the reduced room temperature.